Comment 3 for bug 1981562

I don't have anything super helpful to add, but in trying to learn more about this error, I found the following bug reports [1][2] (emphasis on "reports" as these were closed NOTABUG) which concluded with them being issues in the NFS server itself related to locking.

*If* this issue happens to be the same root cause as [1] and [2], then adding the "nolock" mount option for NFS [3] as a workaround should make the problem disappear:

  [libvirt]
  nfs_mount_options = nolock

(multiple options can be specified with commas between them, see [3])

It might be worth giving that a try and let us know whether it has any effect on your scenario.

[1] https://bugzilla.redhat.com/show_bug.cgi?id=1817640
[2] https://bugzilla.redhat.com/show_bug.cgi?id=1891673
[3] https://docs.openstack.org/nova/latest/configuration/config.html#libvirt.nfs_mount_options